It sounds absolutely fantastic. Other than the low power output (not an issue in my small space), I can't subjectively discern any sonic compromise with this tiny unit.

Even without a sub, the Topping + M3's sitting on my desk sound just great fed by my Mac. I suspect I'm getting some good bass reinforcement from the wall right behind the M3's. I'm sure a small sub would help, but I'm not feeling the lack at the moment for this kind of listening.

The unit seems to have excellent build quality. Very simple, no controls other than power on and volume.

Absurdly cool running. Perfect for an always-on desktop system (provides all sound from the Mac).

It's seems preternatural to get such great sound from such a ridiculously tiny and simple device.

I suspect that if they wanted to Axiom could enter this space of tiny, high quality digital amps in some way at a better price point, perhaps integrated into more of a system. But even if they don't, Topping has it covered quite well.